iOS 5.1 available over the air now, changelog inside

Just hours after the iOS 5.1 update was announced at Apple's iPad event in San Francisco the update is live for you to download.
The update brings Japanese language support for Siri as well as the option to selectively delete photos from Photo Stream in iCloud. Also, the lockscreen camera...

every time i go to settings>general>software update, it says, "unable to check for update. an error occured while checking for update". im afraid to connect to my computer, back up, restore, and lose my game center account. what is wrong with my ipod?